Wisdom. Experience. The stuff which books can't really teach. You have greed? Fine, but now you have something to lose. End game: Either you lose all your stuff, or you lose all your greed.
Greed is good as long as both parties benefit. Eg in trading there are speculators, hedgers and market makers. All can benefit at the same time. When one party screws the other then greed is not good. Outright stealing is obviously not good either.
Ambition is good. Greed? Greed not so much. Ultimately greed is selfishness, and unchecked selfishness is never good.
Some bad use of logic and justifications in the link: 1. The whole is made up by its parts, society is made up of its individuals. So if society is altruistic, self-healing and positively evolving, it is because of good qualities in individuals overpowering bad qualities in the system. Capitalism (the system) is amoral, mostly inert and nonconscious, thus not the source of good deeds and innovation. 2. This is OK reasoning. 3. Trades have no inherent property called mutually beneficial. Capitalism tend to exploit natural resources and poor people to the brink of extermination and extinction. Capitalism is currently threatening mass-extinction of species, biomass diversity, liberty, freedom and democracy. 4. Capitalism tend to burn candles in all ends, disregarding the whole and killing its host. It's just that the processes are very efficient short-term, masquerading the systemic failures, waste and corruption over longer time. It's true that removing capitalism and private ownership is often/generally worse. Trying to rely even more on a system leads to neglect and abuse. But something needs to rein in capitalism as well. 5. Charity with tie-ins and no sustainable way out & up is just another way to enslave people and assert total dominance. People shouldn't have to rely on charity and shouldn't be bound by such regimes either. USA has one of the worst healthcare in the world and fail for its population to be self-sustainable. The West steal just as much or more from unfair trade imbalances, corruption and sabotage, and the foreign aid they do provide are also stolen and destroying the local markets.